Pre-SIP: Export Macros

Language Design
7

I’m not sure if this is possible yet, but if macro annotations are allowed to fill in methods of a trait, I think I’ve come around to the idea that you should avoid generating declarations that typer relies on. That is, val hola = ${MyMacro.dothis(false)} is great, as is

trait HasSomeMethod {
  def classNameAndMethodCount(): (String, Int)
}

@fillInHasSomeMethod
class Foo extends HasSomeMethod {
  def method1(): Int = 5
  def method2(): Boolean = false
   // `@fillInHasSomeMethod quietly generates 
   // def classNameAndMethodCount(): (String, Int) = ("HasSomeMethod", 2)
}

Tooling might still get a little confused about where to bring you for the definition of Foo. classNameAndMethodCount, but it’s no longer totally magical – it could just bring you to the trait.